1. Field of the Invention
The present invention relates to an adjusting structure of an adjusting seat of an injection molding machine, more particularly one, which includes a split-flow hydraulic pump, four hydraulic motors connected to conduits of the split-flow hydraulic pump, four toothed disks on the output portions of the hydraulic motors, and four gears respectively positioned around tie rods and engaging the toothed disks such that position of the adjusting seat can be smoothly adjusted, and the risk of damage reduced.
2. Brief Description of the Prior Art
Referring to FIG. 1, a currently existing injection molding machine 1 includes a first mold support 11, an adjusting seat 12, a second mold support 13, a moving wall 14, four tie rods 15, a toggle arm mechanism 16, and a hydraulic cylinder 17. The first mold support 11 is used for supporting a male part of a mold. The second mold support 13 is arranged between the first mold support 11 and the adjusting seat 12 for supporting a female part of a mold while the moving wall 14 is arranged between the second mold support 13 and the adjusting seat 12. The tie rods 15 are passed through the first mold support 11, the adjusting seat 12, the second mold support 13, and the moving wall 14. The hydraulic cylinder 17 is used to move the moving wall 14 on the tie rods 15 while the toggle arm mechanism 16 is positioned between the second mold support 13 and the adjusting seat 12, and movable together with the moving wall 14; thus, when the hydraulic cylinder 17 is actuated to move the moving wall 14, the toggle arm mechanism 16 will move so as to make the second mold support 13 change its position in relation to the first mold support 11 for mold closing or opening.
Because different molds have different thicknesses, when a new two-part mold is used on the molding machine instead of the original one, the adjusting seat 2 usually has to be adjusted in position such that the two-part mold can be properly closed by means of the hydraulic cylinder 17 and the toggle arm mechanism 16.
Referring to FIG. 2, the adjusting seat 2 has a motor 18, a toothed disk 19, and four gears 10 thereon; the motor 18 is used for causing rotational motion of the toothed disk 19 while the gears 10 are positioned around respective ones of the tie rods 15, and engaged with the toothed disk 19. Therefore, when the motor 18 is activated, rotational motion of the motor 18 will be transmitted to the gears 10 through the toothed disk 19, and in turn the gears 10 will move linearly on the tie rods 15, thus causing linear displacement of the adjusting seat 12 on the tie rods 15.
However, the above adjusting structure of the adjusting seat has the following disadvantages:
1. The motor has to provide power to the toothed disk alone therefore the motor has to be capable of producing great force. Consequently, consumption of electricity and the cost increases.
2. All power will be concentrated on the currently engaged teeth of the motor and the toothed disk therefore the teeth of the motor and the toothed disk are prone to get damaged, and power won't be effectively transmitted any more.
3. The toothed disk has to precisely engage all of the four gears otherwise power transmission won't be smooth. Therefore, the toothed disk and the gears have to be precision-manufactured, causing increase to the cost as well as time used in the assembly and calibration.
Germany Patent No. DE 4329070 discloses an adjusting structure of an adjusting seat of a molding machine, which includes a belt used to transmit power from single motor to several gears positioned on respective tie rods. Because the motor has to provide power alone, the output thereof has to be relatively large. Consequently, service life of the motor will shorten. In addition, the power transmission can't be very effective because the gears don't have equal force exerted thereon with the belt used as the transmission means.